Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 14: Micromagetic Simulation and Electron Theory of Magnetism

MA 14.6: Vortrag

Dienstag, 12. März 2013, 10:45–11:00, H23

Magnetic phase transitions of ferromagnetic and antiferromagnetic alloys from first principles — •Konstantin Tillmanns, Phivos Mavropoulos, and Stefan Blügel — Peter Grünberg Institut and Institute forAdvanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

We investigate a wide spectrum of ordered and disordered magnetic alloys concerning their magnetization, half metallicity and Curie/Néel temperature using an ab initio approach. We employ the Korringa-Kohn-Rostoker (KKR) Green function method [1] for the electronic structure and the method of infinitesimal rotations [2] for the exchange coupling parameters. These are derived both from the ground state and from the disordered local moment (DLM) state [3] and utilized in a Heisenberg model whose thermodynamical properties are studied by Monte Carlo simulations. By this we locate the magnetic phase transition. We furthermore focus on a comparison of the critical temperatures calculated by the different theoretical approaches (ground-state and DLM starting points) with experimental data.

[1] N. Papanikolaou, R. Zeller, and P.H. Dederichs, J. Phys. Condens. Matter 14, 2799 (2002); H. Ebert, D. Ködderitzsch and J. Minár, Rep. Prog. Phys. 74, 096501 (2011); see also http://www.kkr-gf.org.

[2] A.I. Liechtenstein et. al., J. Magn. Magn. Mater. 67, 65 (1987).

[3] H. Akai and P.H. Dederichs, Phys. Rev. B 47, 8739 (1993).